| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elaltxp | ⊢ ( 𝑧  ∈  ( 𝐴  ××  𝐵 )  ↔  ∃ 𝑥  ∈  𝐴 ∃ 𝑦  ∈  𝐵 𝑧  =  ⟪ 𝑥 ,  𝑦 ⟫ ) | 
						
							| 2 |  | df-altop | ⊢ ⟪ 𝑥 ,  𝑦 ⟫  =  { { 𝑥 } ,  { 𝑥 ,  { 𝑦 } } } | 
						
							| 3 |  | snssi | ⊢ ( 𝑥  ∈  𝐴  →  { 𝑥 }  ⊆  𝐴 ) | 
						
							| 4 |  | ssun3 | ⊢ ( { 𝑥 }  ⊆  𝐴  →  { 𝑥 }  ⊆  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 5 | 3 4 | syl | ⊢ ( 𝑥  ∈  𝐴  →  { 𝑥 }  ⊆  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 6 | 5 | adantr | ⊢ ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐵 )  →  { 𝑥 }  ⊆  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 7 |  | elun1 | ⊢ ( 𝑥  ∈  𝐴  →  𝑥  ∈  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 8 |  | snssi | ⊢ ( 𝑦  ∈  𝐵  →  { 𝑦 }  ⊆  𝐵 ) | 
						
							| 9 |  | vsnex | ⊢ { 𝑦 }  ∈  V | 
						
							| 10 | 9 | elpw | ⊢ ( { 𝑦 }  ∈  𝒫  𝐵  ↔  { 𝑦 }  ⊆  𝐵 ) | 
						
							| 11 |  | elun2 | ⊢ ( { 𝑦 }  ∈  𝒫  𝐵  →  { 𝑦 }  ∈  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 12 | 10 11 | sylbir | ⊢ ( { 𝑦 }  ⊆  𝐵  →  { 𝑦 }  ∈  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 13 | 8 12 | syl | ⊢ ( 𝑦  ∈  𝐵  →  { 𝑦 }  ∈  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 14 | 7 13 | anim12i | ⊢ ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐵 )  →  ( 𝑥  ∈  ( 𝐴  ∪  𝒫  𝐵 )  ∧  { 𝑦 }  ∈  ( 𝐴  ∪  𝒫  𝐵 ) ) ) | 
						
							| 15 |  | vex | ⊢ 𝑥  ∈  V | 
						
							| 16 | 15 9 | prss | ⊢ ( ( 𝑥  ∈  ( 𝐴  ∪  𝒫  𝐵 )  ∧  { 𝑦 }  ∈  ( 𝐴  ∪  𝒫  𝐵 ) )  ↔  { 𝑥 ,  { 𝑦 } }  ⊆  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 17 | 14 16 | sylib | ⊢ ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐵 )  →  { 𝑥 ,  { 𝑦 } }  ⊆  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 18 |  | prex | ⊢ { { 𝑥 } ,  { 𝑥 ,  { 𝑦 } } }  ∈  V | 
						
							| 19 | 18 | elpw | ⊢ ( { { 𝑥 } ,  { 𝑥 ,  { 𝑦 } } }  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 )  ↔  { { 𝑥 } ,  { 𝑥 ,  { 𝑦 } } }  ⊆  𝒫  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 20 |  | vsnex | ⊢ { 𝑥 }  ∈  V | 
						
							| 21 |  | prex | ⊢ { 𝑥 ,  { 𝑦 } }  ∈  V | 
						
							| 22 | 20 21 | prsspw | ⊢ ( { { 𝑥 } ,  { 𝑥 ,  { 𝑦 } } }  ⊆  𝒫  ( 𝐴  ∪  𝒫  𝐵 )  ↔  ( { 𝑥 }  ⊆  ( 𝐴  ∪  𝒫  𝐵 )  ∧  { 𝑥 ,  { 𝑦 } }  ⊆  ( 𝐴  ∪  𝒫  𝐵 ) ) ) | 
						
							| 23 | 19 22 | bitri | ⊢ ( { { 𝑥 } ,  { 𝑥 ,  { 𝑦 } } }  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 )  ↔  ( { 𝑥 }  ⊆  ( 𝐴  ∪  𝒫  𝐵 )  ∧  { 𝑥 ,  { 𝑦 } }  ⊆  ( 𝐴  ∪  𝒫  𝐵 ) ) ) | 
						
							| 24 | 6 17 23 | sylanbrc | ⊢ ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐵 )  →  { { 𝑥 } ,  { 𝑥 ,  { 𝑦 } } }  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 25 | 2 24 | eqeltrid | ⊢ ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐵 )  →  ⟪ 𝑥 ,  𝑦 ⟫  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 26 |  | eleq1a | ⊢ ( ⟪ 𝑥 ,  𝑦 ⟫  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 )  →  ( 𝑧  =  ⟪ 𝑥 ,  𝑦 ⟫  →  𝑧  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 ) ) ) | 
						
							| 27 | 25 26 | syl | ⊢ ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐵 )  →  ( 𝑧  =  ⟪ 𝑥 ,  𝑦 ⟫  →  𝑧  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 ) ) ) | 
						
							| 28 | 27 | rexlimivv | ⊢ ( ∃ 𝑥  ∈  𝐴 ∃ 𝑦  ∈  𝐵 𝑧  =  ⟪ 𝑥 ,  𝑦 ⟫  →  𝑧  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 29 | 1 28 | sylbi | ⊢ ( 𝑧  ∈  ( 𝐴  ××  𝐵 )  →  𝑧  ∈  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 ) ) | 
						
							| 30 | 29 | ssriv | ⊢ ( 𝐴  ××  𝐵 )  ⊆  𝒫  𝒫  ( 𝐴  ∪  𝒫  𝐵 ) |